1. Field of the Invention
The present invention relates to a magnetic tape drive machine, and it particularly relates to a machine for driving a magnetic tape appropriate to a tape cartridge for backing up a magnetic disk unit.
2. Field of the Invention
A well known type of tape cartridge for backing up a magnetic disk comprises a drive belt for rotating a pair of reels as well as a protective cover which functions to expose a part of a magnetic tape to bring a magnetic head into sliding contact with the exposed part of the tape only when the tape cartridge is loaded in a prescribed recording/reproduction position. The protective cover extends along only a fraction of the long edge of the cartridge and rotates in the plane of the cartridge. In a tape drive machine employing such a tape cartridge, a cartridge loading mechanism, a magnetic head moving mechanism and so forth are simplified if the cartridge is inserted in the direction of the width of the tape drive machine. In that case, however, since the width of the tape cartridge needs to be not less than the length of the cartridge, the width of the tape drive machine is made larger than that of the magnetic disk unit which is combined with the machine.
For that reason, a magnetic tape drive machine has been proposed in which a tape cartridge is loaded in the longitudinal direction of the machine in order to reduce its width. Such magnetic tape drive machines were disclosed in the Japanese Patent Application (OPI) No. 213056/84 (the term "OPI" as used herein means an "unexamined published application"), in the Japanese Patent Application (OPI) No. 45459/86 and in the Japanese Patent Application (OPI) No. 123048/86.
There is a mechanism for bringing a magnetic head and a tape into contact with each other by swinging in the magnetic head on the same plane as a cartridge to put the head into contact with the tape such as that disclosed by Barton et al in U.S. Pat. No. 4,573,091. However it is hard to achieve an adequate amount of swing within the magnetic head within a limited width. The magnetic head is thus necessarily located near a cartridge insertion passage. As a result, it is likely that the cartridge hooks the magnetic head when the cartridge is inserted.
In the magnetic tape drive machine disclosed in the Japanese Patent Application (OPI) No. 213056/84, a cartridge is put on a tray and conveyed into the machine in order not to come into contact with a magnetic head. For that reason, the construction of the machine is complicated. As for a cartridge of such kind, a protective cover needs to be opened along with the insertion of the cartridge into the machine. A construction for opening the protective cover is also complicated.
In the magnetic tape drive machine disclosed in the Japanese Patent Application (OPI) No. 45459/86, a direct drive system is adopted in order to prevent the fluctuation in the speed of movement of a magnetic tape. A cartridge is inserted into the machine as the protective cover of the cartridge is located at the outer portion of the cartridge, so that the protective cover is opened. For that reason, a mechanism for opening the protective cover is complicated.
In the magnetic tape drive machine disclosed in the Japanese Patent Application (OPI) No. 123048/86, a cartridge is inserted with its protective cover located at the inner portion of the cartridge. Since its magnetic head needs to be moved through a long distance not to hinder the opening and closing of a protective cover, a mechanism for moving the magnetic head is complicated and a large space is required for the movement of the magnetic head. Since the mechanism precludes the adoption of a direct drive system, a capstan motor is provided in a more internal position than the magnetic head to drive a capstan in a belt drive system.